Incorporated in the treaty of commerce between Japan and France, completed in 1858, was a provision for the construction of a chapel for French nationals. Oura Tenshu-do was built in 1864 to satisfy to this provision. The name is a Sino-Japanese rendering of a Catholic church. The official name is Nihon Niju-roku Seijin Junkyosha Tenshu-do (Chapel of the Heavenly Father for the Twenty-six Martyred Japanese Saints) relates to the 26 Japanese Christian martyrs of 1597.Due to a lack of funding, the construction of the Tenshu-do was held up, and the roof had to be made with wooden tiles. The red brick building was finally completed in 1914. It was destroyed by the atomic bomb in 1945, but rebuilt with steel-frame ferro-concrete in 1959. The Tenshu-do is designated as a National Treasure.